Comparison report on CS and PAVA Sprays

Publication Number: 24/14

Management Summary

This report has been compiled at the request of the National Policing Lead on Self Defence Arrest and Restraint (SDAR) to provide information on the similarities and differences between CS and PAVA sprays. It is based on a previous comparative study published in 20041, which reviewed the two approved chemical irritant solutions that were available at the time: CS in MIBK and PAVA in 50% aqueous (referred to in this document as PAVA 1). Since the publication of the 2004 review, a new solvent formulation for PAVA has been approved: PAVA in monopropylene glycol, ethanol and water (referred to in this document as PAVA 2).

The report details the technical differences between all three approved chemical irritant solutions, and compares the operational experience of officers using the sprays via information collected from officers who have used at least two of the approved sprays. Officers were asked to give a direct comparison from their experience; therefore the data collected are purely subjective and opinion‐based.

The overarching theme discussed by officers when comparing CS and PAVA sprays was cross contamination of CS sprays compared with the accuracy required to use PAVA sprays. Both had benefits and disadvantages which have been described in this document. The other significant difference between the sprays is their flammability, which may be a consideration when assessing the risks when deploying the sprays with Taser; CS and PAVA 1 are flammable, PAVA 2 is non‐flammable.

It is intentional that this report does not contain a conclusion. The Centre for Applied Science and Technology (CAST) recognise that there are benefits and disadvantages of each spray and, as forces have different operational needs, it is better that the decision regarding which chemical irritant spray to deploy is made locally rather than as a national standard. It is conceivable that there may be a place for both within certain forces for use in different operational situations.

1 Comparison of CS and PAVA: Operational and Toxicological Aspects.

Contents

1. Introduction ...... 4 1.1 History of chemical irritants for UK Police ...... 4 1.2 Comparative studies ...... 5 1.3 Review of 2004 study ...... 5

2. Technical Aspects ...... 6 2.1 Chemical composition ...... 6 2.2 Discharge rate ...... 7 2.3 Flammability ...... 7 2.4 Compatibility with other police equipment ...... 8

3. Operational Aspects: Questionnaire Responses ...... 9

4. Summary of Differences Between Sprays...... 15

5. Statements from the Committees on Toxicity, Mutagenicity and Carcinogenicity of Chemicals in Food, Consumer Products and the Environment ...... 17

6. Acknowledgements ...... 20

7. Glossary ...... 21

Appendix A ...... 23

Appendix B ...... 24

Appendix C ...... 25

3 Comparison Report on CS and PAVA sprays

1. Introduction

1.1 History of chemical irritants for UK Police

In 1994 CAST (then PSDB) were requested to identify a chemical irritant spray for police use, to meet the Police Operational Requirement. Opinion at the time favoured the use of Oleoresin Capsicum (OC, commonly referred to as ) as it was already in use in the United States and some other countries. CAST consulted internationally recognised experts in the field of medicine, pathology and toxicology to establish the suitability of OC from a toxicological point of view. It soon became apparent that information on the toxicological profile of OC was lacking. Conversely, the amount of toxicological information on CS was vast; indeed the Department of Health advised that “CS was thoroughly tested to the same standards as those to which new drugs are subjected and its properties are well understood”. A shift in emphasis from OC to CS resulted. This culminated in the then Home Secretary giving his full support to the issue of a CS‐based irritant spray in August 1996 following a successful six‐ month trial. The formulation finally adopted had been used in France since 1984 and comprised a 5% solution of CS in the solvent methyl isobutyl ketone (MIBK).

CS was adopted as standard issue to routine patrol officers by all but three forces in England and Wales. Although deploying CS spray, Hertfordshire Constabulary were independently pursuing the possibility of using an alternative irritant spray based on pelargonic acid vanillylamide or PAVA. PAVA is a synthetic product based on one of the active components of OC. The advantage of PAVA over OC was that it is a single compound which makes its toxicological profile easier to assess. Sussex Police started a pilot trial with PAVA in April 2001.

In May 2002 the information available on PAVA (0.3% PAVA in a solvent of 50% aqueous ethanol) was referred to the Department of Health Independent Committees on Toxicity, Mutagenicity and Carcinogenicity in Food, Consumer Products and the Environment. The same Committees had produced a statement on the health effects of CS spray in 1999 with the overall conclusion that “the available data did not, in general, raise concerns regarding the health effects of CS itself”. When the Committee produced a statement on PAVA in 2002 they recommended further work as they could not make an assessment on the health effects using the available data. These data were collected over the next two years and the Committee reconsidered PAVA in September 2004 concluding “the available information, both from the toxicity data in experimental studies, and experience in use, indicates that the low exposures arising from the use of PAVA incapacitant spray would not be expected to be associated with any significant adverse health effects”. Following ministerial support for the use of PAVA, chief officers now had a choice of chemical irritant spray.

In 2007 the Committee commented on the proposal for the reformulation of PAVA spray (marketed as Captor 2 or Captor II). This comprised 0.3% PAVA in monopropylene glycol, ethanol and water. The Committee concluded that “the information submitted on the toxicological risk assessment of Captor II in relation to direct and indirect exposure, provided adequate reassurance that the risk was lower than

4 Comparison Report on CS and PAVA sprays for the previous formulation”.

All three irritant solutions are now approved for use in chemical irritant spray devices. The Committee Statements on all three solutions have been summarised in Section 5 and reproduced in the appendices.

In order to avoid confusion with the term ‘incapacitant’ which is used to describe tranquillisers and other similar drugs in the Chemical Weapons Convention the term ‘Chemical Irritant’ will be used to refer to CS and PAVA in this report.

1.2 Comparative studies

CAST produced the first comparative study of CS and PAVA sprays in 2004. This focused on operational aspects, based on discussions with officers who had used both CS and PAVA sprays from the only force at the time that had issued both sprays (North Wales). This was a subjective assessment as there are many factors that may influence the opinion of each spray and its effectiveness; therefore the information presented did not focus on statistics but what the officers thought.

The report also included the statements from the Independent Committees on Toxicity, Mutagenicity and Carcinogenicity in Food, Consumer Products and the Environment.

1.3 Review of 2004 study

This report focuses primarily on the technical differences between the three approved solutions as well as comparisons of operational experience from officers who have used at least two of the three solutions.

Many more forces are now using PAVA sprays and there is a greater level of operational experience, due to the time that has passed since the introduction of chemical irritant sprays in the UK. CAST c